In a back contact solar cell, to form a p-type semiconductor layer and an n-type semiconductor layer on the back surface of a semiconductor substrate, an insulation layer is provided between the p-type semiconductor layer and the n-type semiconductor layer.
According to Japanese Unexamined Patent Application Publication No. 2012-28718 (Patent Literature (PTL) 1), after a p-type or n-type semiconductor layer is formed on the back surface of a semiconductor substrate, an insulation layer is formed on the p-type or n-type semiconductor layer. The insulation layer is first etched with an acidic etchant and patterned, by photolithography. The patterned insulation layer is then used as a mask, to etch the p-type or n-type semiconductor layer with an alkaline etchant.
According to Japanese Unexamined Patent Application Publication No. 2008-529265 (PTL 2), an insulation layer and an amorphous semiconductor layer are formed on the back surface of a semiconductor substrate, and each layer is etched by laser etching or an etching paste to manufacture a solar cell having an interdigital structure.